It is a personality trait that is forged in childhood. While anyone can behave vainly at any given time in their life, it is most often a stable pattern to life. If it is a personality trait difficult to modify, although it is not impossible.
Like all personality traits, arrogance can be more or less easily acquired. One can be more or less extroverted, more or less responsible, the extreme of arrogance is a Narcissistic Personality Disorder.